Slurry Erosion Resistance of Microwave Derived Ni-SiC Composite Claddings

Silicon - Hydro machinery components such as turbines, pipes, guide vanes, and pumps suffer from severe slurry erosion caused by the abrasive particles entrained in working fluid. In the current...     

LoCaL: Link-optimized cone-assisted location routing in flying ad hoc networks

Recently, flying ad hoc networks (FANETs) has become a core research area in wireless networks that involves multiple unmanned aerial vehicles (UAVs). It is widely used in modern warfare for surveillance, monitoring and reconnaissance. The routing in FANETs poses a more significant challenge due to limited energy and frequent link disconnection between the UAVs. Consequently, an effective route is always required to ensure data transmission between UAVs. Therefore, this research proposes a link-optimized cone-assisted location (LoCaL) routing protocol for FANETs. The main goal of the proposed LoCaL is to enhance the link duration between the UAVs in which a source selects a forwarding UAV from a given set of neighbours by estimating the residual energy, link duration time and safety degree parameters. Proposed LoCaL provides better stability and less frequent route breaks between source and destination. Further, the mathematical formulation of the proposed approach is presented through the utility function to enhance the route stability by selecting all those relay UAVs in the cone-shaped request zone, which reduces the routing overhead in discovering the route. Finally, the performance of the LoCaL has been presented through key indicators such as energy consumption, routing overhead, message delivery ratio, network lifetime and delay compared to the existing approaches.     

Positive and Negative Pressure Regimes in Anisotropically Strained V2O3 Films

The metal-insulator phase transitions in V₂O₃ are considered archetypal manifestations of Mott physics. Despite decades of research, the effects of doping, pressure, and anisotropic strains on the transitions are still debated. To understand how these parameters control the transitions, anisotropically strained pure V₂O₃ films are explored with nearly the same contraction along the c-axis, but different degrees of ab-plane expansion. With small ab-plane expansion, the films behave similar to bulk V₂O₃ under hydrostatic pressure. However, with large ab-plane expansion, the films are driven into the “negative pressure” regime, similar to that of Cr-doped V₂O₃, exhibiting clear coexistence of paramagnetic insulator and paramagnetic metal phases between 180–500 K. This shows that c-axis contraction alone, or an increase in c/a ratio is insufficient for inducing “negative pressure” effects. Actually, c-axis contraction alone destabilizes the two insulating phases of V₂O₃, whereas a-axis expansion tends to stabilize them. The effects of strain are modeled using density functional theory providing good agreement with experimental results. The findings show that chemical pressure alone cannot account for the phase diagram of (V_1−xCr_x)₂O₃. This work enables to manipulate a Mott transition above room temperature, thereby expanding the opportunities for applications of V₂O₃ in novel electronics.     

A comprehensive review on solar thermal desalination systems based on humidification-dehumidification approach

Clean Technologies and Environmental Policy - Fresh water scarcity is turning into a serious and worrying challenge to the sustainable growth of human being. This issue highlights the...     

Synthesis and Characterization of High-Entropy CrMoNbTaVW Thin Films Using High-Throughput Methods

High-entropy alloys (HEAs) or complex concentrated alloys (CCAs) offer a huge research area for new material compositions and potential applications. Since the combination of several elements sometimes leads to unexpected and unpredictable material properties. In addition to the element combinations, the optimization of the element proportions in CCAs and HEAs is also a decisive factor in tailoring desired material properties. However, it is almost impossible to achieve the composition and characterization of CCAs and HEAs with a sufficient number of compositions by conventional experiments. Therefore, an optimized high-throughput magnetron sputtering synthesis to fabricate a new HEA gradient layer of six elements is presented. With this approach, the compositional space of the HEA system CrMoNbTaVW can be studied in different subsections to determine the influence of the individual elements and their combinations on the structure, morphology, and physical properties (hardness and resistivity). It is found that the Cr-, Ta-, and W-rich phases, which have a grain size of 10–11 nm, exhibit the hardest mechanical properties, whereas V-, Ta-, and Cr-rich compounds exhibit the highest electrical resistivity. The combination of high-throughput synthesis, automated analysis tools, and automated data interpretation enables rapid and time-efficient characterization of the novel CrMoNbTaVW gradient film.     

Hole-doped high entropy ferrites: Structure and charge compensation mechanisms in (Gd0.2La0.2Nd0.2Sm0.2Y0.2)1−xCaxFeO3

High entropy oxides (HEOs) can be defined as single-phase oxide solid solutions with five or more cations in near equiatomic proportion occupying a given cation sub-lattice. The compositional flexibility while retaining the phase purity can be considered one of the major strengths of this materials class. Taking advantage of this aspect, here we explore the extent to which an aliovalent hole dopant can be incorporated into a perovskite-HEO system. Nine systems, (Gd_0.2La_0.2Nd_0.2Sm_0.2Y_0.2)_1−xCa_xFeO₃, with varying amount of Ca content (x = 0–.5) are synthesized using nebulized spray pyrolysis. Single-phase orthorhombic (Pbnm) structure can be retained up to 20% of Ca doping. Beyond 20% of Ca, a secondary rhombohedral (R-3c) phase emerges. The ⁵⁷Fe Mössbauer spectra indicate that charge compensation occurs only via oxygen vacancy formation in the single-phase systems containing up to 15% of Ca. In addition, partial transition from Fe³⁺ to Fe⁴⁺ occurs in the 20% Ca-doped case. Room temperature Mössbauer spectroscopy further reflects the coexistence of multiple magnetic phases in crystallographic single-phase (Gd_0.2La_0.2Nd_0.2Sm_0.2Y_0.2)_1−xCa_xFeO₃, which is supported by magnetometry measurements. These initial results show the potential of charge doping to tune structural–magneto–electronic properties in compositionally complex HEOs, warranting further research in this direction.     

Real geo-time-based secured access computation model for e-Health systems

Role Back Access Control model (RBAC) allows devices to access cloud services after authentication of requests. However, it does not give priority in Big Data to devices located in certain geolocations. Regarding the crisis in a specific region, RBAC did not provide a facility to give priority access to such geolocations. In this paper, we planned to incorporate Location Time- (GEOTime) based condition alongside Priority Attribute role-based access control model (PARBAC), so requesters can be allowed/prevented from access based on their location and time. The priority concept helped to improve the performance of the existing access model. TIME-PARBAC also ensures service priorities based on geographical condition. For this purpose, the session is encrypted using a secret key. The secret key is created by mapping location, time, speed, acceleration and other information into a unique number, that is, K(Unique_Value) = location, time, speed, accelerator, other information. Spatial entities are used to model objects, user position, and geographically bounded roles. The role is activated based on the position and attributes of the user. To enhance usability and flexibility, we designed a role schema to include the name of the role and the type of role associated with the logical position and the rest of the PARBAC model proposed using official documentation available on the website for Azure internet of things (IoT) Cloud. The implementation results utilizing a health use case signified the importance of geology, time, priority and attribute parameters with supporting features to improve the flexibility of the existing access control model in the IoT Cloud.     

Experimental Investigation and Analysis on Borosilicate Glass Using Electrochemical Discharge Machining Process

Silicon - Electrochemical discharge machining process (ECDM) is a non-traditional machining process which has widely used in medical, electronics and aerospace industry. This paper discuss about...     

Green Synthesis-Mediated Silver Nanoparticles Based Biocomposite Films for Wound Healing Application

Journal of Inorganic and Organometallic Polymers and Materials - Wound care is a clinical challenge due to the susceptibility of the wound to multidrug-resistant bacterial infections. We report a...